Showing papers in "Obesity in 2007"

High-fat diets: modeling the metabolic disorders of human obesity in rodents.

Abstract: Research Methods and Procedures: High-fat (HF) diet feeding can induce obesity and metabolic disorders in rodents that resemble the human metabolic syndrome. However, this dietary intervention is not standardized, and the HF-induced phenotype varies distinctly among different studies. The question which HF diet type is best to model the metabolic deterioration seen in human obesity remains unclear. Therefore, in this review, metabolic data obtained with different HF diet approaches are compiled. Both whole-body and organ-specific diet effects are analyzed. Results: On the basis of these results, we conclude that animal fats and ω-6/ω-9-containing plant oils can be used to generate an obese and insulin-resistant phenotype in rodents, whereas fish oil-fed animals do not develop these disorders. Discussion: Looking at the present data, it does not seem possible to define an ideal HF diet, and an exact definition of diet composition and a thorough metabolic characterization of the HF diet effects in a researcher's specific laboratory setting remains essential for metabolic studies with this model.

Physical activity assessment with accelerometers: an evaluation against doubly labeled water

Abstract: This review focuses on the ability of different accelerometers to assess daily physical activity as compared with the doubly labeled water (DLW) technique, which is considered the gold standard for measuring energy expenditure under free-living conditions. The PubMed Central database (U.S. NIH free digital archive of biomedical and life sciences journal literature) was searched using the following key words: doubly or double labeled or labeled water in combination with accelerometer, accelerometry, motion sensor, or activity monitor. In total, 41 articles were identified, and screening the articles' references resulted in one extra article. Of these, 28 contained sufficient and new data. Eight different accelerometers were identified: 3 uniaxial (the Lifecorder, the Caltrac, and the CSA/MTI/Actigraph), one biaxial (the Actiwatch AW16), 2 triaxial (the Tritrac-R3D and the Tracmor), one device based on two position sensors and two motion sensors (ActiReg), and the foot-ground contact pedometer. Many studies showed poor results. Only a few mentioned partial correlations for accelerometer counts or the increase in R(2) caused by the accelerometer. The correlation between the two methods was often driven by subject characteristics such as body weight. In addition, standard errors or limits of agreement were often large or not presented. The CSA/MTI/Actigraph and the Tracmor were the two most extensively validated accelerometers. The best results were found for the Tracmor; however, this accelerometer is not yet commercially available. Of those commercially available, only the CSA/MTI/Actigraph has been proven to correlate reasonably with DLW-derived energy expenditure.

Consistent Self‐monitoring of Weight: A Key Component of Successful Weight Loss Maintenance

Abstract: Objective: The objectives were to investigate the characteristics associated with frequent self-weighing and the relationship between self-weighing and weight loss maintenance. Research Methods and Procedures: Participants (n = 3003) were members of the National Weight Control Registry (NWCR) who had lost ≥30 lbs, kept it off for ≥1 year, and had been administered the self-weighing frequency assessment used for this study at baseline (i.e., entry to the NWCR). Of these, 82% also completed the one-year follow-up assessment. Results: At baseline, 36.2% of participants reported weighing themselves at least once per day, and more frequent weighing was associated with lower BMI and higher scores on disinhibition and cognitive restraint, although both scores remained within normal ranges. Weight gain at 1-year follow-up was significantly greater for participants whose self-weighing frequency decreased between baseline and one year (4.0 ± 6.3 kg) compared with those whose frequency increased (1.1 ± 6.5 kg) or remained the same (1.8 ± 5.3 kg). Participants who decreased their frequency of self-weighing were more likely to report increases in their percentage of caloric intake from fat and in disinhibition, and decreases in cognitive restraint. However, change in self-weighing frequency was independently associated with weight change. Discussion: Consistent self-weighing may help individuals maintain their successful weight loss by allowing them to catch weight gains before they escalate and make behavior changes to prevent additional weight gain. While change in self-weighing frequency is a marker for changes in other parameters of weight control, decreasing self-weighing frequency is also independently associated with greater weight gain.

Short sleep duration is associated with reduced leptin levels and increased adiposity: Results from the Quebec family study.

Abstract: CHAPUT, JEAN-PHILIPPE, JEAN-PIERRE DESPRES, CLAUDE BOUCHARD, AND ANGELO TREMBLAY. Short sleep duration is associated with reduced leptin levels and increased adiposity: results from the Quebec Family Study. Obesity. 2007;15:253-261. Objective: To explore cross-sectional associations between short sleep duration and variations in body fat indices and leptin levels during adulthood in a sample of men and women involved in the Quebec Family Study. Research Methods and Procedures: Anthropometric mea- surements, plasma lipid-lipoprotein profile, plasma leptin concentrations, and total sleep duration were determined in a sample of 323 men and 417 women ages 21 to 64 years. Results: When compared with adults reporting 7 to 8 hours of sleep per day, the adjusted odds ratio for overweight/ obesity was 1.38 (95% confidence interval, 0.89 to 2.10) for those with 9 to 10 hours of sleep and 1.69 (95% confidence interval, 1.15 to 2.39) for those with 5 to 6 hours of sleep, after adjustment for age, sex, and physical activity level. In each sex, we observed lower adiposity indices in the 7- to 8-hour sleeping group than in the 5- to 6-hour sleeping group. However, all of these significant differences disap- peared after statistical adjustment for plasma leptin levels. Finally, the well-documented regression of plasma leptin levels over body fat mass was used to predict leptin levels of short-duration sleepers (5 and 6 hours of sleep), which were then compared with their measured values. As ex- pected, the measured leptin values were significantly lower than predicted values. Discussion: There may be optimal sleeping hours at which body weight regulation is facilitated. Indeed, short sleep duration predicts an increased risk of being overweight/ obese in adults and is related to a reduced circulating leptin level relative to what is predicted by fat mass. Because sleep duration is a potentially modifiable risk factor, these find- ings might have important clinical implications for the prevention and treatment of obesity.

A green tea extract high in catechins reduces body fat and cardiovascular risks in humans.

Abstract: NAGAO, TOMONORI, TADASHI HASE, AND ICHIRO TOKIMITSU. A green tea extract high in catechins reduces body fat and cardiovascular risks in humans. Obesity. 2007; 15:1473–1483. Objective: The body fat reducing effect and reduction of risks for cardiovascular disease by a green tea extract (GTE) high in catechins was investigated in humans with typical lifestyles. Research Methods and Procedures: Japanese women and men with visceral fat-type obesity were recruited for the trial. After a 2-week diet run-in period, a 12-week doubleblind parallel multicenter trial was performed, in which the subjects ingested green tea containing 583 mg of catechins (catechin group) or 96 mg of catechins (control group) per day. Randomization was stratified by gender and body mass index at each medical institution. The subjects were instructed to maintain their usual dietary intake and normal physical activity. Results: Data were analyzed using per-protocol samples of 240 subjects (catechin group; n 123, control group; n 117). Decreases in body weight, body mass index, body fat ratio, body fat mass, waist circumference, hip circumference, visceral fat area, and subcutaneous fat area were found to be greater in the catechin group than in the control group. A greater decrease in systolic blood pressure (SBP) was found in the catechin group compared with the control group for subjects whose initial SBP was 130 mm Hg or higher. Low-density lipoprotein (LDL) cholesterol was also decreased to a greater extent in the catechin group. No adverse effect was found. Discussion: The continuous ingestion of a GTE high in catechins led to a reduction in body fat, SBP, and LDL cholesterol, suggesting that the ingestion of such an extract contributes to a decrease in obesity and cardiovascular disease risks.

A community intervention reduces BMI z-score in children: Shape Up Somerville first year results

Abstract: Results: At baseline, 44% (n 385), 36% (n 561), and 43% (n 232) of children were above the 85th percentile for BMI z-score in the intervention and the two control communities, respectively. In the intervention community, BMI z-score decreased by 0.1005 (p 0.001, 95% confidence interval, 0.1151 to 0.0859) compared with children in the control communities after controlling for baseline covariates. Discussion: A community-based environmental change intervention decreased BMI z-score in children at high risk for obesity. These results are significant given the obesigenic environmental backdrop against which the intervention occurred. This model demonstrates promise for communities throughout the country confronted with escalating childhood obesity rates.

Waist Circumference and Cardiometabolic Risk: A Consensus Statement from Shaping America's Health: Association for Weight Management and Obesity Prevention; NAASO, The Obesity Society; the American Society for Nutrition; and the American Diabetes Association

Abstract: Obesity is an important risk factor for cardiometabolic diseases, including diabetes, hypertension, dyslipidemia, and coronary heart disease (CHD). Several leading national and international institutions, including the World Health Organization (WHO) and the National Institutes of Health, have provided guidelines for classifying weight status based on BMI (1,2). Data from epidemiological studies demonstrate a direct correlation between BMI and the risk of medical complications and mortality rate (e.g., 3,4). Men and women who have a BMI ≥30 kg/m2 are considered obese and are generally at higher risk for adverse health events than are those who are considered overweight (BMI between 25.0 and 29.9 kg/m2) or lean (BMI between 18.5 and 24.9 kg/m2). Therefore, BMI has become the “gold standard” for identifying patients at increased risk for adiposity-related adverse health outcomes. Body fat distribution is also an important risk factor for obesity-related diseases. Excess abdominal fat (also known as central or upper-body fat) is associated with an increased risk of cardiometabolic disease. However, precise measurement of abdominal fat content requires the use of expensive radiological imaging techniques. Therefore, waist circumference (WC) is often used as a surrogate marker of abdominal fat mass, because WC correlates with abdominal fat mass (subcutaneous and intra-abdominal) (5) and is associated with cardiometabolic disease risk (6). Men and women who have waist circumferences greater than 40 inches (102 cm) and 35 inches (88 cm), respectively, are considered to be at increased risk for cardiometabolic disease (7). These cut points were derived from a regression curve that identified the waist circumference values associated with a BMI ≥30 kg/m2 in primarily Caucasian men and women living in north Glasgow (8). An expert panel, organized by the National Heart, Lung and Blood Institute, has recommended that WC be measured as part …

Trends in pre-pregnancy obesity in nine states, 1993-2003.

Abstract: KIM, SHIN Y., PATRICIA M. DIETZ, LUCINDA ENGLAND, BRIAN MORROW, AND WILLIAM M. CALLAGHAN. Trends in pre-pregnancy obesity in nine states, 1993–2003. Obesity. 2007;15:986–993. Objective: Pre-pregnancy obesity poses risks to both pregnant women and their infants. This study used a large population-based data source to examine trends, from 1993 through 2003, in the prevalence of pre-pregnancy obesity among women who delivered live infants. Research Methods and Procedures: Data from the Pregnancy Risk Assessment Monitoring System in nine states were analyzed for trends in pre-pregnancy obesity (BMI 29.0 kg/m 2 ) overall and by maternal demographic and behavioral characteristics. Pre-pregnancy BMI was calculated from self-reported weight and height on questionnaires administered after delivery, and demographic characteristics were taken from linked birth certificates. The sample of 66,221 births was weighted to adjust for survey design, non-coverage, and non-response, and it is representative of all women delivering a live birth in each particular state. The sampled births represented 18.5% of all births in the United States. Results: Pre-pregnancy obesity increased 69.3% during the study period, from 13.0% in 1993 to 1994 to 22.0% in 2002 to 2003. The percentage increase ranged from 45% to 105% for individual states. Subgroups of women with the highest prevalence of obesity in 2002 to 2003 were those who were 20 to 29 years of age, black, had three or more children, had a high school education, enrolled in Women, Infants, and Children, or were non-smokers. However, all subgroups of women examined experienced at least a 43% increase in pre-pregnancy obesity over this time period. Discussion: The prevalence of pre-pregnancy obesity is increasing among women in these nine states, and this trend has important implications for all stages of reproductive health care.

The validity of obesity based on self-reported weight and height: Implications for population studies.

Abstract: Objective: To validate self-reported information on weight and height in an adult population and to find a useful algorithm to assess the prevalence of obesity based on self-reported information. Research Methods and Procedures: This was a crosssectional survey consisting of 1703 participants (860 men and 843 women, 30 to 75 years old) conducted in the community of Vara, Sweden, from 2001 to 2003. Self-reported weight, height, and corresponding BMI were compared with measured data. Obesity was defined as measured BMI >= 30 kg/m(2). Information on education, self-rated health, smoking habits, and physical activity during leisure time was collected by a self-administered questionnaire. Results: Mean differences between measured and self-reported weight were 1.6 kg (95% confidence interval, 1.4; 1.8) in men and 1.8 kg (1.6; 2.0) in women (measured higher), whereas corresponding differences in height were -0.3 cm (-0.5; -0.2) in men and -0.4 cm (-0.5; -0.2) in women (measured lower). Age and body size were important factors for misreporting height, weight, and BMI in both men and women. Obesity (measured) was found in 156 men (19%) and 184 women (25%) and with self-reported data in 114 men (14%) and 153 women (20%). For self-reported data, the sensitivity of obesity was 70% in men and 82% in women, and when adjusted for corrected self-reported data and age, it increased to 81 % and 90%, whereas the specificity decreased from 99% in both sexes to 97% in men and 98% in women. Discussion: The prevalence of obesity based on self-reported BMI can be estimated more accurately when using an algorithm adjusted for variables that are predictive for misreporting.

Associations Between the Home Food Environment and Obesity‐promoting Eating Behaviors in Adolescence

Abstract: Objective: This study examines relationships between multiple aspects of the home food environment and obesity-promoting characteristics of 12- to 13-year-old adolescents' diets, specifically frequency of consumption of high-energy fluids, sweet snacks, savory snacks, and take-out foods. Research Methods: This was a cross-sectional study including 347 adolescents 12 to 13 years of age and their parents. Data were collected via self-completed surveys. The adolescents' diets were assessed using a Food Frequency Questionnaire derived from existing age-appropriate National Nutrition Survey data. An extensive range of domains within the home food environment were assessed. Bivariate linear regression analyses were run split by gender. Forced entry multiple linear regression analyses (adjusting for all variables significant in bivariate analyses as well as for maternal education) were also performed, stratified by the sex of the child. Results: The influence of mothers, either as models for eating behaviors or as the providers of food, was pervasive. Mothers' intake of high-energy fluids (p = 0.003), sweet snacks (p = 0.010), savory snacks (p = 0.008), and take-out food (p = 0.007) was positively associated with boys' intake of all these foods. In addition, mothers' intake of high-energy fluids was positively associated with daughters' consumption of these drinks (p = 0.025). Furthermore, availability of unhealthy foods at home was positively associated with girls' sweet snack (p = 0.001), girls' savory snack (p Discussion: This study of home food environment influences on adolescent diet highlights the pervasive influence of mothers in determining adolescents' obesity-promoting eating, providing direction for obesity prevention strategies and future research.

Comparison of Self-reported and Measured BMI as Correlates of Disease Markers in U.S. Adults

Abstract: Objective: The purpose of this study is to evaluate the validity of BMI based on self-reported data by comparison with technician-measured BMI and biomarkers of adiposity. Research Methods and Procedures: We analyzed data from 10,639 National Health and Nutrition Education Study III participants ≥20 years of age to compare BMI calculated from self-reported weight and height with BMI from technician-measured values and body fatness estimated from bioelectrical impedance analysis in relation to systolic blood pressure, fasting blood levels of glucose, high-density lipoprotein-cholesterol, triglycerides, C-reactive protein, and leptin. Results: BMI based on self-reported data (25.07 kg/m2) was lower than BMI based on technician measurements (25.52 kg/m2) because of underreporting weight (−0.56 kg; 95% confidence interval, −0.71, −0.41) and overreporting height (0.76 cm; 95% confidence interval, 0.64, 0.88). However, the correlations between self-reported and measured BMI values were very high (0.95 for whites, 0.93 for blacks, and 0.90 for Mexican Americans). In terms of biomarkers, self-reported and measured BMI values were equally correlated with fasting blood glucose (r = 0.43), high-density lipoprotein-cholesterol (r = −0.53), and systolic blood pressure (r = 0.54). Similar correlations were observed for both measures of BMI with plasma concentrations of triglycerides and leptin. These correlations did not differ appreciably by age, sex, ethnicity, or obesity status. Correlations for percentage body fat estimated through bioelectrical impedance analysis with these biomarkers were similar to those for BMI. Discussion: The accuracy of self-reported BMI is sufficient for epidemiological studies using disease biomarkers, although inappropriate for precise measures of obesity prevalence.

Internalization of weight bias: Implications for binge eating and emotional well-being.

Abstract: Objective: This study examined the relationship between internalization of negative weight-based stereotypes and indices of eating behaviors and emotional well-being in a sample of overweight and obese women. Research Method and Procedures: The sample was comprised of 1013 women who belonged to a national, non-profit weight loss organization. Participants completed an on-line battery of self-report questionnaires measuring frequency of weight stigmatization and coping responses to deal with bias and symptoms of depression and self-esteem, attitudes about weight and obesity, and binge eating behaviors. In addition, participants were asked to list the most common weight-based stereotypes and whether they believed them to be true or false. Results: Participants who believed that weight-based stereotypes were true reported more frequent binge eating and refusal to diet in response to stigma experiences compared with those who reported stereotypes to be false. The degree to which participants believed stereotypes to be true or false was not related to types or amount of stigma experiences reported, self-esteem, depression, or attitudes toward obese persons. In addition, engaging in weight loss strategies as a response to bias was not predicted by stereotype beliefs or by actual stigma experiences, regardless of the amount or types of stigma reported. Discussion: These findings suggest that obese individuals who internalize negative weight-based stereotypes may be particularly vulnerable to the negative impact of stigma on eating behaviors and also challenge the notion that stigma may motivate obese individuals to engage in efforts to lose weight. This study highlights a new area of research that warrants attention to better understand weight stigma and its potential consequences for health.

Metabolic and behavioral compensatory responses to exercise interventions: barriers to weight loss.

Abstract: An activity-induced increase in energy expenditure theoretically disturbs energy balance (EB) by creating an acute energy deficit. Compensatory responses could influence the weight loss associated with the energy deficit. Individual variability in compensation for perturbations in EB could partly explain why some individuals fail to lose weight with exercise. It is accepted that the regulatory system will readily defend impositions that promote a negative EB. Therefore, a criticism of exercise interventions is that they will be ineffective and futile methods of weight control because the acute energy deficit is counteracted. Compensation for exercise-induced energy deficits can be categorized into behavioral or metabolic responses and automatic or volitional. An automatic compensatory response is a biological inevitability and considered to be obligatory. An automatic compensatory response is typically a metabolic consequence (e.g., reduced resting metabolic rate) of a negative EB. In contrast, a volitional compensatory response tends to be deliberate and behavioral, which the individual intentionally performs (e.g., increased snack intake). The purpose of this review is to highlight the various metabolic and behavioral compensatory responses that could reduce the effectiveness of exercise and explain why some individuals experience a lower than expected weight loss. We propose that the extent and degree of compensation will vary between individuals. That is, some individuals will be predisposed to compensatory responses that render them resistant to the weight loss benefits theoretically associated with an exercise-induced increase in energy expenditure. Therefore, given the inter-individual variability in behavioral and metabolic compensatory responses, exercise prescriptions might be more effective if tailored to suit individuals.

Shifts in patterns and consumption of beverages between 1965 and 2002.

Abstract: DUFFEY, KIYAH J., AND BARRY M. POPKIN. Shifts in patterns and consumption of beverages between 1965 and 2002. Obesity. 2007;15:2739–2747. Background: Beverage patterning may play a role in partially explaining the rising rates of obesity in the United States, yet little work on overall trends and patterns exits. Our objective was to examine trends and patterns of beverage consumption among U.S. adults. Methods: We used data from the nationally representative Nationwide Food Consumption Surveys (1965, 1977 to 1978) and the National Health and Nutrition Surveys (1988 to 1994, 1999 to 2002). To examine trends we determined percent consuming and per capita and per consumer caloric intake from all beverages. We used cluster analysis to determine year-specific beverage patterns in 1977 and 2002. Results: The percentage of calories from beverages significantly increased between 1965 (11.8%), 1977 (14.2%), 1988 (18.5%), and 2002 (21.0%); this represents an overall increase of 222 calories per person per day from beverages, resulting largely from increased intake of calorically sweetened beverages. Beverage patterns in 2002 were more complex than in 1977 and were dominated by a greater number of beverages, reflecting the increase in alcohol, soda, and diet beverages. Conclusion: Calories from beverages increased substantially from 1965 to 2002, providing a considerable source of daily calories. Given the upward trends in calorically sweetened, nutrient-deficient beverages and the shifts in overall beverage patterns, addressing beverage intake is a salient issue for adults.

Is rural residency a risk factor for overweight and obesity for U.S. children

Abstract: LUTFIYYA, MAY NAWAL, MARTIN S. LIPSKY, JENNIFER WISDOM-BEHOUNEK, AND MELISSA INPANBUTR-MARTINKUS. Is rural residency a risk factor for overweight and obesity for U.S. children? Obesity. 2007;15:2348–2356. Objective: Despite studies suggesting that there is a higher prevalence of overweight or obese children in rural areas in the U.S., there are no national studies comparing the prevalence levels of overweight or obese rural to metropolitan children. The objective of this research was to examine the hypothesis that living in a rural area is a risk factor for children being overweight or obese. Research Methods and Procedures: Using the National Survey of Children’s Heath, the prevalence of overweight and/or obese rural children was compared with that of children in metropolitan settings. Multivariate analyses were performed on the data to detect if differences varied by health services use factors or demographic factors, such as household income, gender, and race. Results: Multivariate analysis revealed that overweight or obese children 5 years of age were more likely to live in rural rather than metropolitan areas (odds ratio 1.252; 95% confidence interval, 1.248, 1.256). Rural overweight U.S. children 5 years of age of age were more likely than their metropolitan counterparts to: be white, live in households 200% of the federal poverty level, have no health insurance, have not received preventive health care in the past 12 months, be female, use a computer for non-school work 3 hours a day, and watch television for 3 hours a day. In addition, they were more likely to have comorbidities. Discussion: Living in rural areas is a risk factor for children being overweight or obese.

The effect of large portion sizes on energy intake is sustained for 11 days.

Abstract: Objective: A previous study showed that increasing the portion sizes of all foods led to an increase in energy intake that was sustained over 2 days. The objective of the present study was to determine whether participants would compensate for excess energy intake or continue to overeat when portion sizes were increased for 11 days. Research Methods and Procedures: Participants in the study were 23 normal-weight and overweight participants (10 women and 13 men). All of their foods and caloric beverages were provided during two different periods of 11 consecutive days, which were separated by a 2-week interval. During one period, standard portions of all items were served; during the other, all portion sizes were increased by 50%. Results: The 50% increase in portion sizes resulted in a mean increase in daily energy intake of 423 ± 27 kcal (p < 0.0001), which did not differ significantly between women and men. This increase was sustained for 11 days and did not decline significantly over time, leading to a mean cumulative increase in intake of 4636 ± 532 kcal. A significant effect of portion size on intake was seen at all meals and in all categories of foods except fruit (as a snack) and vegetables. The effect of portion size on intake was not influenced by the body weight status of participants. Discussion: These results strengthen the evidence suggesting that increased portions contribute to the overconsumption of energy and to excess body weight.

First nationwide survey of prevalence of overweight, underweight, and abdominal obesity in Iranian adults.

Abstract: 25.2% of women were obese (BMI 30), while 6.3% of men and 5.2% of women were underweight. Age, low physical activity, low educational attainment, marriage, and residence in urban areas were strongly associated with obesity. Abdominal obesity was more common among women than men (54.5% vs. 12.9%) and greater with older age. Discussion: Excess body weight appears to be common in Iran. More women than men present with overweight and abdominal obesity. Prevention and treatment strategies are urgently needed to address the health burden of obesity.

Does excess pregnancy weight gain constitute a major risk for increasing long-term BMI?

Abstract: Objective: The objective was to assess the relevance of the recommendations of the Institute of Medicine (IOM), regarding gestational weight gain (GWG) for long-term BMI development. Research Methods and Procedures: The Stockholm Pregnancy and Women's Nutrition is a follow-up study of 483 women who delivered children in 1984 to 1985. ANOVA was used to examine the change in body weight before pregnancy, at 6 months, and 1 year postpartum and 15 years after childbirth. Multiple linear regression was used to assess the predictors of BMI at 15-year follow-up. Results: The weight increase from baseline to 15-year follow-up was 6.2 kg for IOM-insufficient, 6.7 kg for IOM-recommended, and 10.0 kg for IOM-excessive weight gain (p < 0.01). ANOVA showed a main effect of time, group and group by time interaction. The weight of the women who had excessive GWG was significantly greater at each time-point of follow-up than the weight of those who gained within or below recommendations. GWG was related to BMI at 15-year follow-up even after accounting for several confounders. Women who gained excessive weight during pregnancy had an increase of 0.72 kg/m2 in long-term BMI compared with women who gained within recommendations. Discussion: The findings support the adequateness of IOM guidelines, not only for the pregnancy-related health matters, but also for preventing long-term weight retention after delivery. Healthcare providers should give women appropriate advice for controlling GWG and motivate them to lose pregnancy-related weight during postpartum to prevent future overweight.

Increasing Trends in Waist Circumference and Abdominal Obesity among U.S. Adults

Abstract: Objective: Some studies have shown that abdominal obesity may be a better predictor than overall obesity for disease risks and all-cause mortality. This study sought to examine the recent trends in waist circumference (WC) among adults in the United States. Research Methods and Procedures: Data from the National Health and Nutrition Examination Survey during 1988–1994, 1999–2000, 2001–2002, and 2003–2004 were analyzed to estimate the trends in the mean WC and the prevalence of abdominal obesity. Pooled t tests were used to test the differences in estimates between two time periods. Results: Between the periods of 1988–1994 and 2003–2004, the age-adjusted mean WC increased from 96.0 cm to 100.4 cm among men (p < 0.001) and from 89.0 cm to 94.0 cm among women (p < 0.001); the age-adjusted prevalence of abdominal obesity increased from 29.5% to 42.4% among men (p < 0.001) and from 47.0% to 61.3% among women (p < 0.001). Between the periods of 1999–2000 and 2003–2004, a significant increase occurred in mean WC only among men (from 99.0 cm to 100.4 cm; p = 0.03) and in the prevalence of abdominal obesity among both men (from 37.0% to 42.2%; p = 0.03) and women (from 55.3% to 61.3%; p = 0.04). People with a BMI of 25 to 29 kg/m2 had a greater relative increase in abdominal obesity. Discussion: The mean WC and the prevalence of abdominal obesity among U.S. adults have increased continuously during the past 15 years. Over one-half of U.S. adults had abdominal obesity in the period of 2003–2004.

Neighborhood risk factors for obesity.

Abstract: Objective: The goal of this study was to explore neighborhood environmental factors associated with obesity in a sample of adults living in a major U.S. metropolitan area. Research Methods and Procedures: This was a multi-level study combining data from the U.S. Behavioral Risk Factor Surveillance System with data from the U.S. Census. A total of 15,358 subjects living in 327 zip code tabulation areas were surveyed between 1998 and 2002. The outcome was obesity (BMI >30), and independent variables assessed included individual level variables (age, education, income, smoking status, sex, black race, and Hispanic ethnicity), and zip code level variables (percentage black, percentage Hispanic, percentage with more than a high school education, retail density, establishment density, employment density, population density, the presence of a supermarket, intersection density, median household income, and density of fast food outlets). Results: After controlling for individual level factors, median household income [ relative risk (RR) = 0.992; 95% confidence interval (CI) = 0.990, 0.994] , population density (RR = 0.98; 95% CI = 0.972, 0.990), employment density (RR = 1.004; 95% CI = 1.001, 1.009), establishment density (RR = 0.981 95% CI = 0.964, 0.999), and the presence of a supermarket (RR = 0.893; 95% CI = 0.815, 0.978) were associated with obesity risk. Fast food establishment density was poorly associated with obesity risk. Discussion: Where one lives may affect obesity status. Given the influence of the presence of a supermarket on obesity risk, efforts to address food access might be a priority for reducing obesity.

Developmental Trajectories of Overweight During Childhood: Role of Early Life Factors

Abstract: Objective: Our goal was to identify developmental trajectories of overweight in children and to assess early life influences on these trajectories. Research Methods and Procedures: Participants consisted of 1739 white, black, and Hispanic children who were younger than 2 years at the first survey and were followed up to 12 years of age. Repeated measures of overweight, defined as BMI ≥95th percentile, were used to identify overweight trajectories with a latent growth mixture modeling approach. Results: Three distinct overweight trajectories were identified: 1) early onset overweight (10.9%), 2) late onset overweight (5.2%), and 3) never overweight (83.9%). After adjustment for multiple potential risk factors, male gender [odds ratio (OR), 1.5; 95% confidence interval (CI), 1.0 to 2.2], black ethnicity (OR, 1.7; 95% CI, 1.1 to 2.6), maternal 25 ≤ BMI <30 kg/m2 (OR, 2.2; 95% CI, 1.3 to 3.7) or ≥30 kg/m2 (OR, 5.1; 95% CI, 2.9 to 9.1), maternal weight gain during pregnancy ≥20.43 kg (OR, 1.7; 95% CI, 1.0 to 2.9), and birth weight ≥4000 g (OR, 2.0; 95% CI, 1.2 to 3.4) were associated with an increased risk of early onset overweight. These risk factors, except maternal weight gain, exerted similar effects on late onset overweight. In addition, maternal smoking (OR, 1.6; 95% CI, 0.8 to 3.1) and birth order ≥3 (OR, 2.3; 95% CI, 1.0 to 5.2) were associated with an increased risk of late onset overweight only. Breastfeeding ≥4 months was associated with a decreased risk of both early (OR, 0.7; 95% CI, 0.3 to 1.3) and late onset overweight (OR, 0.7; 95% CI, 0.3 to 1.7). Discussion: Two trajectories of overweight and one never overweight group were identified. Early life predictors may have a significant influence on the developmental trajectories of overweight in children.

Field Validation of the MTI Actigraph and BodyMedia Armband Monitor Using the IDEEA Monitor

Abstract: Objective: Accelerometers offer considerable promise for improving estimates of physical activity (PA) and energy expenditure (EE) in free-living subjects. Differences in calibration equations and cut-off points have made it difficult to determine the most accurate way to process these data. The objective of this study was to compare the accuracy of various calibration equations and algorithms that are currently used with the MTI Actigraph (MTI) and the Sensewear Pro II (SP2) armband monitor. Research Methods and Procedures: College-age participants (n = 30) wore an MTI and an SP2 while participating in normal activities of daily living. Activity patterns were simultaneously monitored with the Intelligent Device for Estimating Energy Expenditure and Activity (IDEEA) monitor to provide an accurate estimate (criterion measure) of EE and PA for this field-based method comparison study. Results: The EE estimates from various MTI equations varied considerably, with mean differences ranging from −1.10 to 0.46 METS. The EE estimates from the two SP2 equations were within 0.10 METS of the value from the IDEEA. Estimates of time spent in PA from the MTI and SP2 ranged from 34.3 to 107.1 minutes per day, while the IDEEA yielded estimates of 52 minutes per day. Discussion: The lowest errors in estimation of time spent in PA and the highest correlations were found for the new SP2 equation and for the recently proposed MTI cut-off point of 760 counts/min (Matthews, 2005). The study indicates that the Matthews MTI cut-off point and the new SP2 equation provide the most accurate indicators of PA.

Dietary fat and weight gain among women in the Nurses' Health Study.

Abstract: Objective: To assess the association of dietary fat and weight gain among adult women and to investigate whether offspring of overweight parents have a greater predisposition to weight gain due to intake of dietary fat. Research Methods and Procedures: This was an 8-year follow-up of 41,518 women in the Nurses’ Health Study (NHS), a population-based, prospective cohort. The women were 41 to 68 years of age, free of cardiovascular disease, cancer, and diabetes in 1986 when “baseline” weight and diet were assessed. Eight years later (1994), changes in weight and dietary intake were assessed. Linear regression models were used to relate change in weight to fat intake and change in fat intake, using the percentage of energy from carbohydrate as the comparison, adjusted for age, BMI in 1986, leisure time physical activity, time spent sitting, percent of calories from protein, and change in percentage of calories from protein. Results: Overall, there was a weak positive association between total fat intake (β = 0.11) and weight gain. Increases in monosaturated and polyunsaturated fat were not associated with weight gain, but increases in animal fat, saturated fat, and trans fat had a positive association with weight change. There was not strong evidence of effect modification by parental weight status (p = 0.7 to 0.8 for percentage of calories from total fat, animal fat, and vegetable fat); however, the associations were stronger among the overweight compared with leaner women (p < 0.05 for percentage of calories from each type of fat). Among overweight women, for every one percentage increase in percentage of calories from trans fat, women gained an additional 2.3 lb (95% confidence interval, 1.80 to 2.86). Conclusion: Our results show that, overall, percent of calories from fat has only a weak positive association with weight gain; however, percentage of calories from animal, saturated, and trans fat has stronger associations. There was no clear evidence that the diet-weight gain association was stronger among offspring of overweight parents, but dietary fat was associated with greater weight gain among overweight women.

Higher protein intake preserves lean mass and satiety with weight loss in pre-obese and obese women

Abstract: LEIDY, HEATHER J, NADINE S CARNELL, RICHARD D MATTES, AND WAYNE W CAMPBELL Higher protein intake preserves lean mass and satiety with weight loss in pre-obese and obese women Obesity 2007; 15:421–429

C57BL/6J and A/J mice fed a high-fat diet delineate components of metabolic syndrome.

Abstract: Objective: The aim of this study was to assess the suitability of A/J and C57BL/6J mice of both sexes as models of some components of the human metabolic syndrome (MetS) under nutritional conditions more comparable with the actual worldwide diet responsible for the increased incidence of the MetS. Research Methods: We fed large cohorts (n = 515) of two strains of mice, A/J and the C57BL/6J, and of both sexes a high-fat diet (HFD; 60% fat) that, in contrast with most previous reports using saturated fats, was enriched in mono- and polyunsaturated fatty acids, thus more closely mimicking most Western diets, or a control diet (10% fat), for 20 weeks. Results: In sharp contrast to previous reports, weight gain and hyperleptinemia were similar in both strains and sexes. Hyperinsulinemia, glucose tolerance, insulin resistance, and hypercholesterolemia were observed, although with important differences between strains and sexes. A/J males displayed severely impaired glucose tolerance and insulin resistance. However, in contrast with C57BL6/J mice, which displayed overt type 2 diabetes, A/J mice of both sexes remained normoglycemic. Discussion: With important differences in magnitude and time course, the phenotypic and metabolic characteristics of both strains and both sexes on this HFD demonstrate that these models are very useful for identifying the mechanisms underlying progression or resistance to subsequent type 2 diabetes.

Weight loss on the web: A pilot study comparing a structured behavioral intervention to a commercial program.

Abstract: Objective: Internet weight loss programs have become widely available as alternatives to standard treatment, but few data are available on their efficacy This study aimed to investigate the effectiveness of a structured behavioral weight loss website (VTrim) vs a commercial weight loss website (eDietscom) Research Methods and Procedures: A randomized, controlled trial was conducted from February 2003 to March 2005, in 124 overweight and obese subjects ages 18 years and older with a BMI of 25 to 399 kg/m2 (mean age, 47 ± 9 years; BMI, 32 ± 3 kg/m2; 20% men) Analyses were performed for the 88 subjects who had complete follow-up data Participants were randomly assigned to 12-month VTrim (n = 62) or eDietscom (n = 62) intervention VTrim participants had access to a therapist-led structured behavioral weight loss program delivered on-line eDietscom subjects had access to a self-help commercial on-line weight loss program Body weight, social support, and use of website components were measured at 0, 6, and 12 months Results: Repeated-measures analyses showed that the VTrim group lost significantly more weight than the eDietscom group at 6 months (83 ± 79 kg vs 41 ± 62 kg; p = 0004) and maintained a greater loss at 12 months (78 ± 75 kg vs 34 ± 58 kg; p = 0002) More participants in the VTrim group maintained a 5% weight loss goal (65% vs 375%; p = 001) at 12 months Discussion: An on-line, therapist-led structured behavioral weight loss website produced greater weight loss than a self-help commercial website Because commercial sites have great potential public health impact, future research should investigate the feasibility of incorporating a more structured behavioral program into a commercial application

Effect of Calorie Restriction on Resting Metabolic Rate and Spontaneous Physical Activity

Abstract: Objective: It is unclear if resting metabolic rate (RMR) and spontaneous physical activity (SPA) decrease in weight-reduced non-obese participants. Additionally, it is unknown if changes in SPA, measured in a respiratory chamber, reflect changes in free-living physical activity level (PAL). Research Methods and Procedures: Participants (N = 48) were randomized into 4 groups for 6 months: calorie restriction (CR, 25% restriction), CR plus structured exercise (CR+EX, 12.5% restriction plus 12.5% increased energy expenditure via exercise), low-calorie diet (LCD, 890 kcal/d supplement diet until 15% weight loss, then weight maintenance), and control (weight maintenance). Measurements were collected at baseline, Month 3, and Month 6. Body composition and RMR were measured by DXA and indirect calorimetry, respectively. Two measures of SPA were collected in a respiratory chamber (percent of time active and kcal/d). Free-living PAL (PAL = total daily energy expenditure by doubly labeled water/RMR) was also measured. Regression equations at baseline were used to adjust RMR for fat-free mass and SPA (kcal/d) for body weight. Results: Adjusted RMR decreased at Month 3 in the CR group and at Month 6 in the CR+EX and LCD groups. Neither measure of SPA decreased significantly in any group. PAL decreased at Month 3 in the CR and LCD groups, but not in the CR+EX group, who engaged in structured exercise. Changes in SPA in the chamber and free-living PAL were not related. Discussion: Body weight is defended in non-obese participants during modest caloric restriction, evidenced by metabolic adaptation of RMR and reduced energy expenditure through physical activity.

Controlled Study of Critical Parent and Family Factors in the Obesigenic Environment

Abstract: Objective: Critical gaps remain in our understanding of the obesigenic family environment. This study examines parent and family characteristics among obese youth presenting for treatment in a clinic setting. Research Methods and Procedures: Families of 78 obese youth (BMI z-score = 2.4; age, 8 to 16 years; 59% girls; 49% African-American) were compared with 71 non-overweight (BMI z-score = −0.02) demographically matched comparisons. Parents completed measures assessing family demographics, psychological distress (Symptom Checklist 90-Revised), and family functioning both broadly (Family Environment Scale: Conflicted, Support, Control) and at mealtimes (About Your Child's Eating-Revised: Mealtime Challenges, Positive Mealtime Interaction). Height and weight were obtained from all participants. Results: Compared with mothers and fathers of non-overweight youth, parents of obese youth had significantly higher BMIs (p < 0.001). Mothers of obese youth reported significantly greater psychological distress (p < 0.01), higher family conflict (p < 0.05), and more mealtime challenges (p < 0.01). Less positive family mealtime interactions were reported by both mothers (p < 0.01) and fathers (p < 0.05) of obese youth. These group differences did not vary by child sex or race. Logistic regression analyses indicated that maternal distress and mealtime challenges discriminated between obese and non-overweight youth after controlling for maternal BMI. Family conflict was explained, in part, by maternal distress. Discussion: Obese youth who present for treatment in a clinic setting are characterized by psychosocial factors at the parent and family level that differ from non-overweight youth. These data are critical because they identify factors that may be serving as barriers to a family's or youth's ability to implement healthy lifestyle behaviors but that are potentially modifiable.

Improved Insulin Sensitivity and Adiponectin Level after Exercise Training in Obese Korean Youth

Abstract: Objective: The objective of this study was to investigate the association among adiposity, insulin resistance, and inflammatory markers [high-sensitivity C-reactive protein (hs-CRP), interleukin (IL)-6, and tumor necrosis factor (TNF)-α] and adiponectin and to study the effects of exercise training on adiposity, insulin resistance, and inflammatory markers among obese male Korean adolescents. Research Methods and Procedures: Twenty-six obese and 14 lean age-matched male adolescents were studied. We divided the obese subjects into two groups: obese exercise group (N = 14) and obese control group (N = 12). The obese exercise group underwent 6 weeks of jump rope exercise training (40 min/d, 5 d/wk). Adiposity, insulin resistance, lipid profile, hs-CRP, IL-6, TNF-α, and adiponectin were measured before and after the completion of exercise training. Results: The current study demonstrated higher insulin resistance, total cholesterol, LDL-C levels, triglyceride, and inflammatory markers and lower adiponectin and HDL-C in obese Korean male adolescents. Six weeks of increased physical activity improved body composition, insulin sensitivity, and adiponectin levels in obese Korean male adolescents without changes in TNF-α, IL-6, and hs-CRP. Discussion: Obese Korean male adolescents showed reduced adiponectin levels and increased inflammatory cytokines. Six weeks of jump rope exercise improved triglyceride and insulin sensitivity and increased adiponectin levels.

The use of BMI and waist circumference as surrogates of body fat differs by ethnicity.

Abstract: Objective: To compare the prediction of percentage body fat using BMI and visceral adipose tissue (VAT) using waist circumference (WC) in individuals of Chinese, European, and South Asian origin. Research Methods and Procedures: Healthy men and women of Chinese, European, and South Asian origin (n = 627) between the ages of 30 and 65 years were recruited to ensure equal distribution of gender and representation across BMI ranges (18.5 to 24.9, 25 to 29.9, and ≥30 kg/m2). Participants were assessed for demographics, anthropometry, lifestyle, and regional adiposity. Percentage body fat and VAT were measured by DXA and computer tomography scan, respectively. Results: BMI and WC were highly correlated with total and regional measures of adiposity in each ethnic group. At any BMI, the percentage body fat of Chinese participants was similar to that of Europeans, but that of South Asians was greater by 3.9% (p < 0.001). Above a WC of 71.0 cm, the Chinese participants had an increasingly greater amount of VAT than the Europeans (p = 0.017 for interaction). South Asians had significantly more VAT than the Europeans at all but the most extreme WC (above 105 cm) (p < 0.05). Discussion: Compared with Europeans, percentage body fat was higher for a given BMI in South Asians, whereas VAT was higher for a given WC in both Chinese and South Asian men and women. These findings support the use of ethnic-specific anthropometric targets.